The Archeological Bronze Age Period (3300 – 1175 B.C.):
The concept of dividing pre-historical ages into systems based on their metal technologies extends far back in European history, but the present archaeological system of the three main ages: stone, bronze and iron, originates with the Danish archaeologist Christian Jürgensen Thomsen (1788–1865), who was the curator of the Museum of Northern Antiquities in Copenhagen (and then later of the National Museum of Denmark) and who was the first to place the system on a more scientific basis by typological and chronological studies, of tools and other artifacts. He first studied the tools and artifacts present in the Museum, then later he broadened his study to bronze implements including many other known tools and artifacts in other locations.
Bronze is an alloy consisting primarily of copper with the addition of other metals (most importantly tin) and sometimes arsenic, phosphorus, aluminum, manganese, and silicon. The addition of small quantities of these elements as impurities in the metal induces irregularities in the atomic crystal lattice structure of the alloy produced, which in turn makes those alloys much harder, more able to hold an edge and much more crack resistant than copper alone.
FYI: Brass is an alloy made of copper and zinc.
An ancient civilization is defined as being in the Bronze Age either because it is known to have smelted and alloyed its own copper, or by that civilization trading for bronze from products which were made elsewhere by another civilization.
The Early Bronze Age (EBA – 3300 – 2200 B.C.):
The initial metal used in early “bronze” age cities is invariably unalloyed copper, which clearly had usefulness to the people of the city, but was not durable enough to be truly useful. Pure copper was utilized more for ornamentation, such as jewelry than for tool production.
The Archeological Middle Bronze Age (MBA – 2200 – 1550 B.C.):
The archeological middle bronze age (MBA) period is generally dated as existing between 2200 B.C. and 1550 B.C., though what distinguished the middle bronze age from the late bronze age is somewhat vague (and perhaps arbitrary), and it varies from one civilization to another.
The Archeological Late Bronze Age (LBA – 1550 – 1175 B.C.) Period:
The archeological late bronze age (LBA) period is generally dated as existing between 1550 B.C. and 1175 B.C.